Among the cyclic polypeptide compounds represented by the above formula (I), a compound wherein R1 is a hydrogen atom and R2 and R3 are hydroxyl groups and a compound wherein R1, R2 and R3 are hydrogen atoms are obtained by a fermentation process disclosed by European Patent No. 0462531 and processes disclosed by WO97/32975 and by WO97/47738. A compound wherein R1 is an acyl group and its production process are disclosed by U.S. Pat. Nos. 5,376,634 and 5,569,646 and WO96/11210 and WO99/40108.
The cyclic polypeptide compounds (I) and their salts are generally unstable to light, humidity, acids, heat and the like. Therefore, desired is development of pharmaceutical preparations in which the cyclic polypeptide compounds and their salts are stabilized.